System and method for milking a group of dairy animals

ABSTRACT

A system for milking a group of animals, in particular cows, comprising an accommodation space in which the animals roam freely, and a plurality of fixed milking stations. A milk storage tank is placed outside the accommodation space. An automatic milking system for automated milking of the animals comprises at least one autonomous self-propelled trolley with milking cups. The milking system automatically connects the milking cups of the trolley to the teats of the animal. A milk discharge system connects the milking cups to the milk storage tank. The milk discharge system comprises flexible milk lines which are connected to the trolley. The trolley is connected to each milking station through a connection in an animal-free space adjacent to the milking stations. The flexible milk line is configured so the trolley can travel from the animal-free space into each of the milking stations while connected to the trolley.

The invention relates to a system and a method for milking a group of milking animals, in particular cows.

EP1188367 discloses a device for automatic milking of animals. The device comprises an automatically movable master station and a number of automatically movable satellite stations. The master station comprises suitable control equipment and a milk reservoir. Furthermore, the master station comprises navigation means and means for locating animals to be milked. The master station can be moved automatically to a group of animals to be milked. The satellite stations comprise milking cups and means for connecting the milking cups. The satellite stations also comprise navigation means and means for locating animals to be milked. The satellite stations can locate, approach and possibly track the animals to be milked in the vicinity of the master station. When they have assumed the correct position relative to the animal to be milked, the animal can be milked automatically. The satellite stations are connected to the master station via flexible milk lines. The self-propelled master station must deliver the milk from the milk reservoir to a milk storage tank. In view of the considerable size of the master station, delivering the milk to the milk storage tank is relatively awkward. In addition, delivery of the milk takes time which cannot be devoted to milking animals, which adversely affects the efficiency of the device. In addition, the milk lines from the satellite stations to the master station can become tangled with each other. Furthermore, the milk lines lie in the accommodation space in which the animals walk around, which entails a risk of stumbling for the animals.

One object of the invention is to provide an improved system for milking a group of milking animals.

This object is achieved according to the invention by a system for milking a group of milking animals, in particular cows, wherein the system comprises:

-   -   an accommodation space for the milking animals, which is         preferably stationary and/or has a fixed floor and/or is fenced         off,     -   a milk storage tank,     -   an automatic milking system for automatic milking of milking         animals,         wherein the milking system comprises at least one autonomous         self-propelled trolley with milking cups, and wherein the         milking system is configured for automatic connection of the         milking cups of the trolley to the teats of a milking animal,         and wherein the milking cups of the trolley are connected to the         milk storage tank by means of a milk discharge system, which         comprises at least one flexible milk line which, preferably at         one end thereof, is connected to the trolley and is in fluid         connection with at least one of the milking cups of the trolley,     -   a plurality of milking stations, preferably stationary milking         stations, which are each placed at a fixed location and next to         each other, preferably laterally next to each other, wherein the         milking stations each comprise an entry opening for entry of a         milking animal from the accommodation space to said milking         station,     -   an animal-free space which is closed for the milking animals in         the accommodation space and extends adjacent to the milking         stations, wherein the animal-free space is connected to each         milking station by means of a connection through which the         trolley can travel, and         wherein the milk storage tank is placed at a fixed location         outside the accommodation space, and the flexible milk line is         configured such that the trolley can travel from the animal-free         space into each of the milking stations while the milk line         remains connected to the trolley and/or the trolley remains         connected to the milk storage tank by means of the milk         discharge system with the milk line.

According to the invention, the milking animals can for example walk freely around the accommodation space. The accommodation space is configured for keeping a production group of milking animals during the lactation phase. The accommodation space is preferably fenced off. The milking stations each comprise an entry opening for entry of a milking animal from the accommodation space to said milking station. Each milking station is configured to receive a single milking animal at a time. The dimensions of the milking station are adapted to the length and width of a single milking animal. Only one milking animal at a time may be present in each milking station.

The milking stations each comprise two long sides and two short sides. The entry opening of each milking station defines one of the short sides of the milking station. The milking stations are preferably arranged with their long sides next to each other. For example, the milking stations are separated from each other on their long sides by fixed separating fences. Each milking station may be limited by a fence at the short side opposite the entry opening. Behind the fence, for example, one or more feed and/or drinking troughs are arranged.

The animal-free space and the milking stations are connected to each other such that the trolley can enter each milking station from the animal-free space. In particular, the floor of each milking station on which a milking animal may stand is connected to the floor of the animal-free space by a connection through which the trolley can travel. The trolley can travel from the floor of the animal-free space over said floor up to the floor of each milking station. The connection through which the trolley can travel between the animal-free space and the milking stations extends under the fence. The trolley can travel from the animal-free space under the fence into each of the milking stations.

The trolley is self-propelled, i.e. the trolley comprises a drive and steering system for driving and steering the trolley. The drive and steering system preferably comprises at least one electric motor. When a milking animal visits one of the milking stations and is ready for milking, the milking system controls the autonomous self-propelled trolley with the milking cups such that the trolley travels automatically over the floor of the animal-free space to the floor of said milking station, up to below the teats of the milking animal.

During travel, the trolley remains connected to the milk storage tank by means of the flexible milk line and other components of the milk discharge system, wherein in contrast to the prior art described above, the milk storage tank is not arranged in a master station which travels automatically through the accommodation space but is placed at a fixed location outside the accommodation space. The flexible milk line is connected at one end to the trolley. The flexible milk line passes through the animal-free space. The configuration of the flexible milk line, in particular its length, diameter, stiffness and/or curvature properties, is such that the trolley can pass over the floor of the animal-free space and reach the floor of all milking stations.

The flexible milk line is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, so that in each milking station the milking cups of the trolley can be connected to the teats of a milking animal present in said milking station. The flexible milk line is adapted to give the trolley a freedom of movement to be able to travel into each milking station, up to below the teats of a milking animal, while the trolley remains connected to the milk storage tank by means of the flexible milk line and other components of the milk discharge system.

When the trolley has travelled to below the animal ready for milking, the milking cups of the trolley are automatically connected to the teats of said milking animal. The milking animal is milked while the milking cups are connected. The milk is discharged from the milking cups, via one or more flexible milk lines and other components of the milk discharge system, to the milk storage tank which is placed at a fixed location outside the accommodation space. Since the milk is discharged to the milk storage tank, the trolley according to the invention need not have its own milking tank. Thus the trolley according to the invention may remain relatively compact. At the same time, with the system according to the invention no time is lost travelling to the milk storage tank to deliver milk. Furthermore, the flexible milk line does not run through the accommodation space, whereby the milking animals walking around the accommodation space are not obstructed by the flexible milk line or able to stumble over this.

According to the invention, it is possible that the milk discharge system is provided with a plurality of flexible milk lines which are each connected at one end to the trolley and are each in fluid connection with one of the milking cups, and a milk/air separator which is arranged at a fixed location, preferably outside the accommodation space, such as in the animal-free space, and wherein each milking cup of the trolley is connected respectively via one of the flexible milk lines to the milk/air separator, and wherein the flexible milk lines are each configured such that the trolley can travel from the animal-free space into each of the milking stations while the milk lines each remain connected to the trolley and/or the trolley remains connected to the milk storage tank by means of the milk discharge system with the milk lines.

Preferably, the trolley comprises four milking cups. The milking cups each comprise a milk outflow opening which is in fluid connection with a respective one of the flexible milk lines, for example via a respective milk hose. A separate flexible milk line is provided for each of the milking cups. The flexible milk lines run from the trolley to the stationary milk/air separator. Both milk and air flow through the milk lines and are received by the milk/air separator, in which the milk and air are separated from each other. The milk/air separator comprises a milk discharge opening which is connected by means of a milk transport line to the milk storage tank. A milk pump is arranged in the milk transport line for pumping the milk. The milk/air separator comprises an air outlet opening to which a vacuum line is connected.

The flexible milk lines form a string or bundle of milk lines, configured such that the trolley can travel from the animal-free space into each milking station, up to below the teats of a milking animal to be milked. Because the milk/air separator is not arranged on the trolley, but for example in the animal-free space, the trolley can remain relatively compact. At the same time, the string of milk lines is configured such that the travelling trolley can reach all milking stations while the milk lines remain connected to the trolley.

In a particular embodiment according to the invention, the milk discharge system comprises a milk/air separator which is arranged on the trolley, and wherein the milking cups are each connected to the milk/air separator, for example by means of a respective milk-carrying hose, and wherein the milk/air separator comprises a milk discharge opening, which is in fluid connection with the end of the flexible milk line connected to the trolley, and wherein the trolley is provided with a milk pump for pumping milk via the flexible milk line to the milk storage tank. Only milk flows through the flexible milk line. Only one milk line is required for transporting the milk. Since the milk pump is arranged on the trolley, the milk can be transported from the trolley to the milk storage tank particularly efficiently. This entails an energy saving. In addition, the milk storage tank may be placed at a relatively great distance from the trolley.

In a preferred embodiment of the invention, the milking system comprises a vacuum source which is arranged at a fixed location, preferably in the animal-free space, wherein the vacuum source is connected via a vacuum system to the milking cups for applying a vacuum to the milking cups, and wherein the vacuum system comprises a flexible vacuum line which, preferably at one end thereof, is connected to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the vacuum line remains connected to the trolley and/or the trolley remains connected to the vacuum source by means of the vacuum system with the vacuum pipe. The vacuum source is for example formed by a vacuum pump. The vacuum system may comprise a pulsator which is arranged on the trolley, wherein the flexible vacuum line at one end thereof is connected to the pulsator. During milking, a substantially constant milking vacuum is maintained in a teat space of the milking cups, while by means of the pulsator a pulsating vacuum pressure is applied in a pulsation space of the milking cups. The teat space and the pulsation space of each milking cup are connected to the vacuum source by the vacuum system. The flexible vacuum line of the vacuum system extends from the trolley through the animal-free space and is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, such that in each milking station, the milking cups of the trolley can be connected to the teats of a milking animal present in the milking station. Because vacuum is supplied to the trolley, the trolley need not have a vacuum pump, so the trolley remains simple and compact. At the same time, the vacuum line has sufficient length and flexibility to allow the trolley to travel to all milking stations.

In one embodiment according to the invention, the milking system comprises an electric power supply source which is arranged at a fixed location, preferably in the animal-free space, and wherein the trolley is connected to the power supply source by means of an electrical connection, wherein the electrical connection comprises a power supply line, which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the power supply line remains connected to the trolley, and/or the trolley remains connected to the power supply source by means of the electrical connection with the power supply line. The power supply source is for example a high-voltage current source. The power supply line is for example a flexible power supply cable. The power supply line connected to the trolley extends from the trolley through the animal-free space and is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, such that in each milking station, the milking cups of the trolley can be connected to the teats of a milking animal present in the milking station. The trolley connected to the power supply source requires no electrical accumulators to supply the electric motors of the trolley with electrical energy. Due to the absence of batteries, the trolley can be designed lighter and more compact. In addition, the trolley need not be charged up and there is no risk of loss of electrical power on the trolley because the batteries have discharged. At the same time, the power supply line, in particular its length, is configured such that during operation the trolley is not obstructed from travelling in each milking station under the teats of an animal to be milked.

According to the invention, it is further preferred that the milking system comprises a water connection which is arranged at a fixed location, preferably in the animal-free space, wherein the trolley is connected to the water connection by means of a water supply system comprising a flexible water line, which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the water line remains connected to the trolley and/or that the trolley remains connected to the water connection by means of the water supply system with the water line. The water connection is connected to the water mains or to another water store. Water from the water connection can be supplied to the trolley by means of the water supply system. The water is for example used to clean and/or rinse the milking cups and/or the milk discharge system. The trolley does not need to carry a water tank because the water is supplied to the trolley via the water supply system. Thus the dimensions of the trolley may remain compact and the weight of the trolley relatively low. In addition, it is not necessary to top up with water because unlimited water is available on the trolley. Thanks to the design with the flexible water line, the trolley can furthermore still travel to all milking stations. The water line extends from the trolley and is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, such that in each milking station, the milking cups of the trolley can be connected to the teats of a milking animal present in the milking station.

Possibly, according to the invention, a cleaning agent such as steam and/or a disinfectant may be added to the water. In this case, it is possible that the cleaning agent is added in the animal-free space and supplied to the trolley via the water supply system. Alternatively, a steam generator and/or a tank for disinfectant may be arranged on the trolley. In this way, the disinfectant may be added on the trolley to the water supplied via the water hose.

According to the invention, it is possible that the milking system comprises a compressed air source which is arranged at a fixed location, preferably in the animal-free space, and wherein the trolley is connected to the compressed air source by means of a compressed air system comprising a flexible compressed air line, which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the compressed air line remains connected to the trolley, and/or the trolley remains connected to the compressed air source by means of the compressed air system with the compressed air line. By means of the compressed air connection, compressed air can be supplied to the trolley. On the trolley, compressed air may be used for example to blow out or evacuate the milking cups and/or the milk discharge system. The flexible compressed air line extends from the trolley and is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, such that in each milking station, the milking cups of the trolley can be connected to the teats of a milking animal present in the milking station. The compressed air connection does not hinder the trolley from serving all milking stations.

In an embodiment according to the invention, the milking system comprises a control system, which may for example comprise a computer, laptop and/or smartphone, wherein the trolley is connected to the control system by means of a hard-wired data connection comprising a flexible data line, which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the data line remains connected to the trolley, and/or the trolley remains connected to the control system by means of the hard-wired data connection with the data line. The data line comprises for example an Ethernet cable. Although the data connection according to the invention may be configured wirelessly, the quantity of data to be transferred from the trolley to the control system and vice versa is sufficiently great for a hard-wired data connection to have advantages. In addition, a wireless connection is in practice less reliable than a hard-wired connection, in particular in a barn for milking animals. The data line extends from the trolley and is configured to enable the trolley to travel over the floor of the animal-free space to the floor of each of the milking stations, such that in each milking station, the milking cups of the trolley can be connected to the teats of a milking animal present in the milking station. While the flexible data line remains connected to the trolley, the trolley can travel under the teats of an animal to be milked in all milking stations.

According to the invention, it is possible that the milking system is provided with a detection system for detecting the teats of a milking animal, wherein the detection system is provided with a camera, in particular for making three-dimensional images, which is arranged on the trolley and wherein the camera is connected to the control system for receiving an image signal from the camera, and wherein the control system is configured for determining the position of the teats on the basis of the image signal received. The image signal from the camera may be connected by means of the hard-wired data connection described above to the control system of the milking system.

In a preferred embodiment, the milking system comprises a, preferably stationary, coupling device which is arranged at a fixed location in the animal-free space, wherein the trolley is connected to the coupling device by means of a flexible connecting string which is configured such that the trolley can travel from the animal-free space into each of the milking stations while the connecting string remains connected to the trolley, and/or the trolley remains connected to the coupling device by means of the flexible connecting string, and wherein the connecting string comprises the milk line and/or the milk lines and/or the vacuum line and/or the power supply line and/or the water line and/or the compressed air line and/or the data line. Said one or more lines extend for example through a flexible sleeve, such as a ribbed plastic tube. The one or more lines of the flexible string is/are connected to the trolley at a first end and to the coupling device at the opposite second end. The coupling device forms the connection of the one or more lines to the fixed world. By means of the coupling device, the milk line and/or milk lines and/or vacuum line and/or power supply line and/or water line and/or compressed air line and/or the data line of the flexible string are connected respectively to the milk storage tank and/or the vacuum source and/or the power supply source and/or the water connection and/or the compressed air source and/or the control system. Because several lines are held together in the flexible string, it is guaranteed that the trolley can travel unhindered over the floor of the animal-free space to all milking stations.

Preferably, the coupling device comprises a first connector device, wherein the flexible connecting string, at an end remote from the trolley, is provided with a second connector device which can be releasably coupled to the first connector device for connecting the milk line and/or milk lines and/or the vacuum line and/or the power supply line and/or the water line and/or the compressed air line and/or the data line. When the first and second connector devices are coupled together, the one or more milking lines and the water line are substantially connected fluid-tightly, and the vacuum line and compressed air line are substantially connected air-tightly. The electrical power supply line is connected electrically isolated. The releasable connection between the first and second connector devices has advantages for service and maintenance activities. If the trolley requires maintenance or fails, the trolley can easily be disconnected. In this case, it is also furthermore possible that the trolley is then replaced by another trolley. The trolley need not be maintained or repaired on the farm, but can be collected or dispatched for maintenance and/or repair. The system according to the invention can in the meantime remain in operation with the replacement trolley.

In one embodiment, the animal-free space also comprises a floor which extends below the level of the connection through which the trolley can travel, whereby the animal-free space is lowered relative to the milking stations. Maintenance of the trolley is now easy to perform because personnel present on the floor of the animal-free space can easily reach the level of the floor with the trolley. The invention is therefore very suitable for converting existing milking pits and/or milking carousels, and making them suitable for milking with the automatic milking system with at least one autonomous, self-propelled trolley. The animal-free space may also be a cellar which is provided with a roof which, at least partly, lies at the level of the floor of the accommodation space and connects thereto, and via which the animals can walk from the milking station via the cellar roof to the accommodation space.

According to the invention, it is preferred that the animal-free space comprises a floor, wherein each milking station comprises a floor provided with a first floor part which is connected, via a connection through which the trolley can travel, to the floor of the animal-free space, and a second floor part which is raised relative to the first floor part, and wherein the trolley is configured to travel from the animal-free floor, at each milking station, under the second floor part, to the first floor part of said milking station and back. The length of the second floor part, viewed in the longitudinal direction of each milking station, is such that if a milking animal stands in said milking station with its front legs on the second floor part, while the rear legs of said milking animal stand on the first floor part. The length of the second floor part is for example between 30-110 cm. The raised second floor part is arranged for example 10-40 cm higher than the first floor part. Such a raised position corresponds substantially to the normal height difference between a lying stall and the floor in a barn. The milking animals are easily able and accustomed to step up such a height.

The trolley is designed such that the trolley can travel under the raised second floor part of each milking station, to under the teats of a milking animal in the milking station in order to connect the milking cups. The trolley can thus connect the milking cups to the teats of said milking animal efficiently and reliably. In addition, the milking stations can be placed directly adjacent to each other, because the trolley need not travel sideways between the front and rear legs in order to reach the teats. This is particularly favorable for the visit of the milking animals to the milking stations, because the milking animals are herd animals which are more inclined to enter a milking station next to other milking animals.

According to the invention, it is preferred that the milking cups of the trolley can be tilted between a retracted or collapsed or folded down state, in which the trolley with the milking cups can travel under the second floor part, and an erected or folded up state, in which the milking cups are tilted up relative to the retracted state, in particular are oriented substantially vertically upward. In order to allow the milking animals to take the step from the first to the second floor part easily and comfortably with their front legs, the second floor part is arranged relatively low. The height available between the floor of the animal-free space and the underside of the raised second floor part is limited. In the erected state, the milking cups protrude above the underside of the second floor part. The milking trolley with the erected milking cups cannot therefore travel below the second floor part. The trolley comprises a tilt drive, which for example comprises an electric drive motor, for tilting the milking cups from the erected state to the retracted state. The tilt drive is actively connected to the control system of the milking system. To allow the trolley to travel from the floor of the animal-free space under the second floor part, the milking cups of the trolley are tilted into the retracted state, for example into a substantially horizontal position. The trolley then fits under the second floor part. The trolley with the retracted milking cups can therefore travel under the raised second floor part up to the first floor part, under the teats of a milking animal. Then the milking cups are tilted into the erected state, whereupon the milking cups can be connected to the teats of the milking animal.

In this case, it is possible that the milking stations comprise at least one feed and/or drinking trough which is arranged at the head ends of the milking stations opposite the entry openings, such that a milking animal present in one of the milking stations must stand with its front legs on the second floor part of said milking station in order to eat and/or drink from the feed and/or drinking trough. By means of eating and/or drinking, the milking animals are motivated to place their front legs on the second floor part. A milking animal which stands with its front legs on the second floor part has a position and/or an attitude which is suitable for connecting the milking cups of the trolley. Connection of the milking cups can therefore take place rapidly and precisely.

In one embodiment, the system comprises an animal identification system for identifying each milking animal present in one of the milking stations. For example, the animal identification system comprises transponders which are arranged on each of the milking animals, and also readout units for reading the transponders, wherein one of the readout units is arranged at each milking station. The readout units are preferably arranged at the head end of each milking station. By means of the animal identification system, a milking animal visiting one of the milking stations can be identified. For example, by means of the control system it can be established whether said milking animal complies with a predefined milking criterion, i.e. whether or not it should be milked.

In an embodiment according to the invention, the system comprises a second autonomous, self-propelled trolley, which is provided with a device for pretreatment and/or post-treatment of the teats of a milking animal present in a milking station. The second trolley can pretreat the teats of a milking animal in a milking station, for example clean, disinfect and/or stimulate these, before the first trolley connects the milking cups automatically to the teats. In addition or alternatively, the second trolley can be configured to post-treat the teats of the milked animal, i.e. after the first trolley has milked the milking animal and has travelled away, the second trolley travels under the milked animal for the post-treatment. Therefore, on the one hand the pretreatment and/or post-treatment, and, on the other hand the milking, are carried out by different trolleys. This increases the efficiency of the system. The first trolley may for example begin milking a following animal while the milked animal is post-treated by the second trolley.

Incidentally, the second trolley of the system according to the invention may be configured in the same way as the first trolley. The first trolley is then used for example for a first number of milking stations, which are preferably situated next to each other, while the second trolley milks the milking animals in a second number of other milking stations, which are preferably also situated next to each other. This further improves the efficiency of the system.

In one embodiment according to the invention, the milking stations comprise at least three milking stations, preferably at least four or five, or six or seven or eight milking stations. In particular, the ratio between the number of milking animals to be kept in the accommodation space and the number of milking stations is important. If the accommodation space is configured to keep a predefined number of milking animals, the number of milking stations is preferably adapted to the predefined number of milking animals, such that the system comprises at least one milking station for every 20 milking animals, preferably at least one milking station for every 15 milking animals, further preferably at least one milking station for every 12 milking animals, and most preferably at least one milking station for every 10 milking animals. In other words, the accommodation space is preferably configured to keep a group of a milking animals in the accommodation space, while the milking stations comprise at least q milking stations, wherein a=q*b+r with 0 r b and b 30, preferably b 20 and more preferably b 12, in particular b 10. The number of milking stations according to the invention is relatively large. Thus in practice, it never occurs or rarely occurs that all milking stations are occupied by milking animals at the same time. The number of milking stations according to the invention is selected such that, in practice, almost always one or more milking stations remain free. Thus the milking animals from the group walking around the accommodation space may enter such free milking stations to eat and/or drink. The milking animals thus feel attracted to the milking stations not merely because of the presence of feed and/or drink, but also because milking animals are herd animals. The milking animals are more inclined to enter the milking stations if adjacent milking stations are occupied by other milking animals. At the same time, the milking stations in themselves are relatively inexpensive, because the relatively costly components of the milking system are arranged on the autonomous self-propelled trolley which is shared by all milking stations. In this way the system according to the invention is particularly suitable for attracting the milking animals effectively to the milking stations and at the same time milking them efficiently.

The feature the accommodation space is configured to keep a predefined number of milking animals means that the accommodation space is designed to contain a predefined number of milking animals, such as 60-70 milking animals, during the lactation phase, wherein for example the surface area (m²) of the accommodation space and the number of facilities in the accommodation space is adapted to the predefined number of milking animals to be kept. If the accommodation space comprises a resting area with lying stalls, the number of lying stalls is for example substantially equal to the number of milking animals to be kept, i.e. an accommodation space for containing a group of for example 60 milking animals, preferably comprises approximately 60 lying stalls. In general, in such an accommodation space only one generally known milking robot is installed—a single milking robot for 60 milking animals is normal in practice. According to the invention, the ratio between the number of milking stations and the number of lying stalls is however much greater. In one embodiment in which the rest area of the accommodation space comprises a number of lying stalls for the milking animals, the system comprises at least one milking station for every 20 lying stalls, preferably at least one milking station for every 15 lying stalls, more preferably at least one milking station for every 12 lying stalls, and most preferably at least one milking station for every 10 lying stalls, i.e. for example an accommodation space with 60 lying stalls comprises, according to the invention, 6 milking stations. The feed facilities of the accommodation space, such as one or more concentrate feeding stations and the length of the feed fence, are adapted to the number of milking animals to be kept in the accommodation space.

According to the invention, it is possible that the milking stations, viewed in top view, are designed elongate and arranged with the long sides laterally next to each other. Preferably, the milking stations are adjacent to each other. For example, the milking stations are arranged parallel adjacent to each other laterally, i.e. the entry openings of the milking stations are substantially aligned relative to each other. The milking stations may however also be placed laterally next to each other in an arc, in particular following a circle arc. It is possible in this case that the long sides of the milking stations to some extent run tapering towards each other. The entry openings are preferably situated on the short sides which extend along the outer periphery, while the feed and/or drinking troughs are arranged on the short sides which lie on the inner periphery.

According to a second aspect, the invention relates to a system for milking a group of milking animals, in particular cows, wherein the system comprises:

-   -   an accommodation space for the milking animals, which is         preferably stationary and/or comprises a fixed floor and/or is         fenced off,     -   a plurality of milking stations, preferably stationary milking         stations, which are each arranged at a fixed position and next         to each other, preferably laterally next to each other, wherein         the milking stations each comprise an entry opening for entry of         a milking animal from the accommodation space to said milking         station, wherein the system comprises in particular at least         three milking stations, preferably at least four or five or six         or seven or eight milking stations and/or the number of milking         stations is as described in claim 16 and/or as above, and     -   an automatic milking system for automatic milking of milking         animals, wherein the milking system comprises milking cups and a         robot device which is movable relative to the milking stations,         such that in each milking station, by means of the robot device,         milking cups can be connected automatically to the teats of a         milking animal present in said milking station.

A milking stall with a milking robot is generally known. In the prior art, normally the aim is to achieve as high a utilization level as possible of a milking robot. The milking robot is relatively expensive, so its capacity must be utilized as optimally as possible. With the system according to the invention, the number of milking stations is preferably such that, in practice, almost always one or more milking stations are free. Nonetheless, the system according to the invention is profitable because relatively costly components are shared by several milking stations. The robot device according to the invention is movable to be able to connect milking cups in every milking station, whereby each milking station need not have its own robot device. The costs per milking station according to the invention are relatively low due to the use of a common robot device for the milking stations. Thus there is no economic obstacle to having free milking stations, and the system can economically be designed with an excess number of milking stations.

According to the second aspect of the invention, the robot device can be configured in various ways. In one embodiment, the robot device comprises an autonomous, self-propelled trolley, wherein the milking cups are arranged on the trolley, and wherein the trolley is configured to travel to each milking station, and wherein the trolley is configured for automatic connection of the milking cups of the trolley to the teats of a milking animal present in the milking station. The milking trolley may be configured as described above. For example, each milking station comprises a floor on which a milking animal can stand, and the system furthermore comprises an animal-free space which extends on the side of the milking stations opposite the accommodation space, wherein the animal-free space comprises a floor which is connected to the floor of each milking station via a connection through which the trolley can travel. Initially for example, the trolley is on the floor of the animal-free space. When a milking animal must be milked in one of the milking stations, the milking system controls the trolley such that the trolley automatically travels over the floor of the animal-free space to the floor of said milking station, up to below the teats of the milking animal. The trolley is autonomous and self-propelled, i.e. the trolley comprises a drive and steering system for driving and steering the trolley. The drive and steering system preferably comprises at least one electric motor. When the trolley has travelled to below the animal ready for milking, the milking cups are automatically connected to the teats of said milking animal. The milking animal is milked while the milking cups are connected. After the milking animal has been milked, the trolley can travel back to the floor of the animal-free space. The trolley is then again ready for a following milking in another or possibly the same milking station.

In an alternative embodiment, the robot device according to the second aspect of the invention comprises a robot arm, which is provided with a first arm part which is movably connected to a fixed supporting structure, and at least one second arm part which is movably connected to the first arm part. For example, the first arm part is connected to the supporting structure pivotably about a substantially vertical pivot axis, for example by means of a ball joint, wherein the second arm part is connected telescopically movably to the first arm part. In this case, the milking stations may be positioned around the pivot axis, i.e. the milking stations then lie laterally next to each other following a circle arc, such that the milking stations are oriented with their head sides towards the pivot axis. By moving the first arm part about the pivot axis, the robot arm can be aligned with each of the milking stations for connecting the milking cups in each milking station. The robot arm may however also be guided movably along a guide rail which extends transversely relative to the long sides of the milking stations arranged next to each other. In this case, the robot arm is movable rectilinearly along the guide rail, so that the robot arm can connect the milking cups in each milking station. Such a robot arm for connecting milking cups may be designed and produced reliably using techniques known in themselves in practice.

According to the invention, it is possible that the robot arm is provided with the milking cups. The milking cups are arranged on the robot arm. The milking cups are connected to the robot arm, and the robot arm can connect the milking cups of the robot arm one by one to the teats of a milking animal. Such a robot arm may be produced and used particularly reliably.

In addition, it is possible that the milking system is provided with a milking cup holder which is configured for receiving milking cups which are not being used, wherein the robot arm is provided with at least one gripper member which is configured to take at least one milking cup from the milking cup holder, and connect it to a teat of a milking animal present in one of the milking stations. In this case, the robot arm takes a first milking cup from the milking cup holder and connects said milking cup to a teat, then the robot arm takes a second milking cup from the milking cup holder, and so on. Such a robot arm is comparable to a robot arm of a generally known milking robot and may be produced and used reliably.

Each milking station may comprise a set of milking cups for connection to the teats of a milking animal present in said milking station. Also, the milking cups may for example be arranged in sets in the animal-free space in front of each milking station. It is also possible that a common set of milking cups is shared by several milking stations. The milking cups are then used successively in several milking stations.

In a preferred embodiment according to the second aspect of the invention, the system comprises an animal-free space which is closed for the milking animals in the accommodation space and extends adjacent to the milking stations, wherein the animal-free space comprises a floor, and wherein each milking station comprises a floor which is provided with a first floor part and a second floor part which is raised relative to the first floor part, and wherein the robot device is configured to move from the floor of the animal-free space at each milking station, under the second floor part, to the first floor part of said milking station and back. In this case, it is possible that a milking cup or milking cups, which for example are connected to a robot device configured as a robot arm or are held by a gripper member of a robot arm, can be moved between a retracted or collapsed or folded down state in which the robot device with said milking cup or milking cups can move below the second floor part, and an erected or folded up state in which said milking cup or milking cups are tilted up relative to the retracted state. The robot device with retracted milking cup or milking cups fits under the second floor part. The robot device can move under the raised second floor part up to the first floor part, under the teats of a milking animal. It is then possible to tilt said milking cup or milking cups up into the erected state to be connected to the teats of said milking animal. The feature of claim 14 may also be applied here.

According to the second aspect of the invention, it is furthermore possible that the system comprises a milk storage tank which is placed at a fixed location outside the accommodation space, wherein the milking cups are connected to the milk storage tank by means of a milk discharge system which comprises at least one flexible milk line, wherein the flexible milk line is configured such that the robot device can move from the animal-free space into each of the milking stations while the milk line remains connected to the robot device and/or the robot device remains connected to the milk storage tank by means of the milk discharge system with the milk line. In this case, one or more of the features according to claims 2-10 may be applied, wherein the trolley may however also be a robot arm or other robot device. The properties and advantages of the trolley described above may also be achieved with a robot arm or other robot device.

The invention also relates to a method for milking a group of milking animals, in particular cows, in a system as described above, wherein the method comprises:

-   -   identification of a milking animal in one of the milking         stations,     -   determining whether said milking animal complies with a         predefined milking criterion,     -   if said milking animal complies with the predefined milking         criterion:         -   moving a robot device, for example a trolley or robot arm,             from the animal-free space to said milking station, in             particular from the floor of the animal-free space to the             floor of the milking station,         -   automatic connection of milking cups by means of the robot             device to the teats of said milking animal,         -   milking of said milking animal in said milking station by             means of the milking system while the milking cups are             connected to the teats of said milking animal,         -   disconnection of the milking cups from the teats of said             milking animal after the milking of said milking animal is             completed,         -   moving the robot device from said milking station back to             the animal-free space.

When a milking animal which fulfils the milking criterion enters one of the milking stations, said milking animal is identified and secured. With a robot device which is configured as a trolley, the trolley then travels from the animal-free space to said milking station until the trolley is below the teats of said milking animal. The milking cups of the trolley are connected automatically to the teats of said milking animal and the milking animal is then milked. The milk is discharged via the flexible milk line and transported to the milk storage tank. After the milking process is completed, the milking cups are disconnected and the trolley then returns to the animal-free space. When later another milking animal which fulfils the milking criterion enters another or possibly the same milking station, the trolley travels to said milking station to milk said other milking animal. For example, the milk is discharged via the milk discharge system with the flexible milk line to the milk storage tank, so that the trolley according to the invention can remain relatively compact and no time need be spent travelling to the milk storage tank to deliver the milk. At the same time, the trolley is able to milk the milking animals in all milking stations efficiently.

The invention will now be explained in more detail below with reference to the attached drawing.

FIG. 1 shows a diagrammatic top view of a first embodiment of a system according to the invention.

FIG. 2 shows an enlarged detail II of FIG. 1.

FIGS. 3a and 3b show perspective views of one of the milking stations of the system shown in FIG. 1, wherein the neck lock device is respectively in the free state and in the locked state.

FIGS. 3c and 3d show front views of the milking station shown in FIGS. 3a and 3 b.

FIGS. 4a-4d show side views of one of the milking stations of the system shown in FIG. 1, in which a milking animal is secured and milked.

FIG. 5 shows a diagrammatic top view of a second embodiment of a system according to the invention.

FIGS. 6a-6c show side views of one of the milking stations of the system shown in FIG. 5, in which a milking animal is secured and milked.

FIG. 7 shows a side view in cross section along line VII-VII from FIG. 4 a.

Several inventions are contained in the exemplary embodiments shown. In this description of the figures, several inventions and features thereof are described. Although the exemplary embodiments show these features in combination, these features have significance alone, i.e. these features can be applied independently of each other. In addition, a system according to the invention need not have all features in combination; a system according to the invention may also contain only a number of these features. In other words, a system according to the invention may contain all possible combinations of one or more of these features.

The system shown in FIG. 1 for milking a group of milking animals, in this exemplary embodiment cows 8, is indicated as a whole with 1. The system 1 comprises an accommodation space 2 which is fenced off by walls or fencing 3 a, 3 b, 3 c and a feed fence 4. The accommodation space 2 is stationary, i.e. immovable, in particular non-rotatable. The accommodation space 2 comprises a fixed floor 5, for example a grating or grid floor or a solid floor. The accommodation space 2 is formed by a barn space, i.e.

the cows 8 are inside the barn. The accommodation space 2 may be connected via a selection gate to another accommodation space such as a separation space or a grazing space (not shown).

The accommodation space 2 comprises a feed area for feeding the milking animals, which in this exemplary embodiment is formed by a feed fence 4 and a concentrate feeding station 6. The accommodation space 2 comprises a rest area for resting the cows 8. In this exemplary embodiment, the rest area is formed by lying stalls 9 in which the cows 8 can lie down. The rest area may however also be configured without lying stalls.

The accommodation space 2 is configured to keep a predefined number of cows during the lactation phase. The surface area (m²) of the accommodation space 2 and the facilities in the accommodation space 2 are adapted to the predefined number of cows to be kept. Since almost all cows rest overnight in the accommodation space, in general one lying stall 9 per cow 8 for example is considered the norm, i.e. the number of lying stalls 9 is substantially equal to the number of cows to be contained. In this exemplary embodiment, the accommodation space 2 is configured to keep 60 cows, and the accommodation space 2 therefore comprises 60 lying stalls. Also, for example, the feed facilities of the accommodation space 2, such as the length of the feed fence 4, are adapted to the number of cows to be contained in the accommodation space 2. In this exemplary embodiment, the system 1 comprises six milking stations 10, i.e. there is one milking station per ten cows 8. The number of milking stations 10 may however be greater or smaller, for example the system 1 may also have seven or eight milking stations 10, or four or five milking stations 10. If the accommodation space 2 is configured for more or fewer than 60 cows 8, the number of milking stations 10 is adapted accordingly. The number of milking stations 10 is matched to the number of milking animals to be kept, such that the system 1 comprises at least one milking station 8 for every 20 milking animals 8, preferably at least one milking station 10 for every ten milking animals 8.

The milking stations 10 are each arranged at a fixed location and laterally next to each other. Each milking station 10 has two long sides and two short sides; the milking stations 10 are each elongate. The milking stations 10 are arranged with the long sides laterally adjacent to each other (see FIGS. 1 and 2). In FIGS. 1 and 2, the milking stations 10, seen in top view, are substantially rectangular. The milking stations 10 may however also be configured differently. For example, the milking stations may be placed next to each other following a circle arc (not shown).

The milking stations 10 are mutually separated by separation fences 12 formed by a horizontal and a vertical bar part 13 a, 13 b (see FIGS. 2, 3 a and 3 b). The horizontal bar part 13 a is relatively low, for example around 60-120 cm high. The cows 8 in adjacent milking stations 10 stand closely next to each other and have mutual contact because the milking stations 10 are only separated from each other by the open separation fences 12. In this way, the herding behavior of the cows in the milking stations 10 is reinforced.

The milking stations 10 each comprise an entry opening 11 for entry of a cow 8 from the accommodation space 2 to the milking station 10. The entry opening 11 of each milking station 10 is arranged on one of the short sides of the milking station 10. As shown most clearly in FIGS. 2, 3 a and 3 b, none of the milking stations 10 has an access gate which is operated by an actuator device between an open state in which the entry opening 11 is open, and a closed state in which the entry opening 11 is closed. The entry openings 11 of the milking stations 10 are each open permanently. Incidentally, according to the invention, it is not excluded that a milking station is taken out of use by closing the entry opening of that milking station, so that the milking station is no longer accessible to milking animals, for example for maintenance or cleaning activities in that milking station. During normal operation, the entry openings 11 are however permanently open. If a milking station 10 is not occupied by a cow 8, there is no obstacle to one of the cows 8 entering said milking station 10 from the accommodation space 2. The unoccupied milking stations 10 are totally freely accessible for the cows 8.

On the short sides or head ends opposite to the entry openings 11, the milking stations 10 are mutually aligned along a fixed fence 14 (see FIG. 2). In this exemplary embodiment, the fence 14 for each milking station 10 has two fence parts 15 a, 15 b which, viewed in the transverse direction of the milking station 10, are arranged spaced apart from each other, leaving free a central opening 19 with a first width w₁ such that the neck of a cow 8 can pass through as far as the shoulders. A cow 8 can enter a milking station 10 until the shoulders of the front legs of the cow 8 come to rest against the fence parts 15 a, 15 b on either side of the central opening. Since the fence parts 15 a, 15 b are arranged fixedly, a cow 8 can only leave each milking station 10 by walking backward again through the entry opening 11. The entry opening 11 therefore also forms an exit opening.

Each milking station 10 furthermore comprises a neck lock device 18 which, in this exemplary embodiment, is arranged on the fence parts 15 a, 15 b. The neck lock device 18 of each milking station 10 can be operated by an actuator device 40 between a locked state or secured state (see FIGS. 3b and 3d ), in which a cow 8 in the milking station 10 is held by the neck and hence secured and/or held in the milking station 10, and an open state (see FIGS. 3a and 3c ), in which a cow 8 is free to move its head in and out of the neck lock device 18 and is free to leave the milking station 10. Thus the neck lock device 18 of each milking station 10 can be actively operated. The neck lock device 18 will be described in more detail below.

In this exemplary embodiment, the milking stations 10 have a drinking system 16 which is configured to provide water for the milking animals 8. The drinking system 16 comprises a plurality of drinking troughs 17; each milking station 10 is provided with its own drinking trough 17. The drinking troughs 17 are connected by a pipe system to a water supply, for example a water mains connection. Water from the water mains connection is supplied via the pipe system to the drinking troughs 17. The water in the separate drinking troughs 17 remains relatively fresh, which is favorable for the drinking behavior of the milking animals. It is however also possible that several milking stations 10 have a common drinking trough, or even that a single drinking trough is provided for all milking stations 10 (not shown).

The drinking trough 17 of each milking station 10 is positioned at a distance behind the fence parts 15 a, 15 b of said milking station 10, such that a cow 8 in said milking station 10 must push its head and neck through the central opening 19 between the fence parts 15 a, 15 b, and through the neck lock device 18 in the open state, in order to drink water from the drinking trough 17. In other words, the drinking system 16 is configured such that water can only be reached by a cow 8 in a milking station 10 which has pushed its head and neck through the neck lock device 18 in the open state. In this way, a cow 8 in a milking station 10 which wishes to drink is secured safely and reliably at the neck by the neck lock device 18 of said milking station 10. This will be explained further below.

In order to identify the cows in the milking stations 10, the system 1 has an animal identification system, known in itself, for identifying each milking animal which visits one of the milking stations. The animal identification system comprises for example transponders 23 which are attached to collars worn by the cows 8, and readout units 24 for reading the transponders 23. The readout units 24 are arranged at the head end of each milking station 10, in particular along the fence 14 (see FIG. 2). When a cow 8 walks into one of the milking stations 10 and then pushes its head through the fence 14, the transponder 23 in the collar of the cow 8 is read by the readout units 24 of said milking station 10, so that the cow 8 is identified. A control system 41, for example comprising a computer, laptop and/or smartphone, is actively connected to the readout units 24. The identity of the identified cow 8 is entered in the control system 41.

The cows can be milked in the milking stations 10 by an automatic milking system 20. With an automatic milking system, the cows voluntarily go to the milking stations 10 to be milked. The automatic milking system 20 comprises milking cups 22. The milking system 20 is configured to connect the milking cups 22 automatically to the teats of a cow 8 in a milking station 10, and to milk said cow 8 automatically provided that said cow 8 complies with a predefined milking criterion, i.e. is ready for milking. The milking system 20 comprises the control system 41 or is actively connected therewith. The control system 41 determines whether a cow 8 which is identified on a visit to a milking station 10 fulfils the milking criterion, i.e. must be milked. Different milking criteria are possible, for example on the basis of the time which has elapsed since the last milking of the cow, or on the basis of the expected milk yield, which is dependent on the time since the last milking and the milk production rate in the udders, which can be calculated from historical data from previous milkings of the cow, or still other milking criteria.

The milking stations 10 are placed adjacent to an animal-free space 70 which is closed for the milking animals present in the accommodation space 2. The animal-free space 70 forms a “clean” space, i.e. the cows 8 have no access to the animal-free space 70 and cannot walk there. The animal-free space 70 has a substantially flat floor 71. Various components of the milking system 20 are arranged in the animal-free space 70. This will be explained further below.

The automatic milking system 20 comprises a robot device which is movable relative to the milking stations 10 such that, in each milking station 10, milking cups 22 can be connected automatically by means of the robot device to the teats of a cow 8 present in said milking station 10. The robot device may be configured in various ways, for example as an autonomous self-propelled trolley with milking cups 22 (see FIGS. 1, 2 and 4 a-4 d) or as a robot arm (see for example FIGS. 5 and 6 a-6 c). The various embodiments of the automatic milking system 20 will be described in more detail below.

In the exemplary embodiment shown, the drinking system 16 of the milking stations 10 is the only drinking facility for the cows in the accommodation space 2. In other words, the cows in the accommodation space 2 can only drink from the drinking troughs 17 of the milking stations 10. In order to drink, the cows must visit the milking stations 10. Since the cows 8 must always drink water, the visit frequency to the milking stations 10 is more than sufficient for milking two or three times per day by means of the automatic milking system 20. Thus it is not necessary or scarcely necessary to collect the cows manually for milking. This is a particularly great advantage since, in the prior art, collecting cows which do not voluntarily visit a milking robot, requires manual labor.

Although the cows can only drink in the milking stations 10, at the same time the water intake of the cows necessary for milk production is guaranteed. The number of milking stations 10 according to the invention is relatively great. As indicated above, the accommodation space 2 in this exemplary embodiment is configured to keep a predefined number of 60 milking animals. In the prior art, it is normal to place only one milking robot in such a production group. According to the invention however, six milking stations 10 are provided. With such a number of milking stations, in practice it does not occur or rarely occurs that all milking stations 10 are occupied by cows simultaneously. Even if cows not ready for milking occupy milking stations 10 for drinking without being milked, almost always one or more milking stations 10 remain free in which other cows can drink. Consequently, it is guaranteed that the cows always or almost always have unrestricted access to water.

At the same time, it is economically viable to have a relatively large number of milking stations 10 because the costs per milking station 10 are particularly low, since the relatively costly components of the automatic milking system 20, i.e. the robot device, are shared by the milking stations 10. The robot device is movable relative to the milking stations 10 such that, in each milking station 10, milking cups 22 can be connected automatically by means of the robot device to the teats of a cow 8 present in said milking station 10.

The drinking system 16 of the milking stations 10 is furthermore configured to make water available, in particular in unlimited quantities (ad libitum), for each cow present in one of the milking stations 10, irrespective of whether or not said cow 8 fulfils the milking criterion. In other words, each cow visiting one of the milking stations 10 can drink in said milking station 10, irrespective of whether or not said cow 8 is ready for milking. In this way, the cows are conditioned to associate the milking stations 10 primarily with drinking, and only secondarily with milking. The milking stations 10 form drinking stations for the cows. Consequently, the cows 8 are further encouraged to visit the milking stations 10 voluntarily.

To facilitate the access to water further, the permanently open entry openings 11 of the milking stations 10 can be reached freely and/or unhindered via a walkable connection from the feed fence 4, the concentrate feeding station 6 and from the lying stalls 9 in the accommodation space 2. The accommodation space 2 is configured such that the cows can walk around freely in the accommodation space 2 between the feed fence 4, the lying stalls 9 and each entry opening 11. Totally free cow traffic is possible between the feed fence 4, the lying stalls 9 and the entry openings 11. To drink water, the cows in the accommodation space 2 are able to walk to the drinking system 16 of the milking stations 10 without compulsion and without hindrance.

Therefore with the system according to the invention, not only is it guaranteed that every cow 8 visits the milking stations 10 frequently, whereby no cows or few cows need be collected for milking, but also water is available so easily that the water consumption of the cows is comfortably sufficient for optimum milk production.

Although, in this exemplary embodiment, the drinking system 16 is the only drinking facility for the cows 8 in the accommodation space 2, the system according to the invention may comprise a further drinking facility, for example a drinking trough in the accommodation space 2. The capacity of the further drinking facility is then however selected small enough that, in order to meet their daily water needs, the cows must still visit the milking stations 10.

In this exemplary embodiment, the neck lock device 18 of each milking station 10 (see FIGS. 3a-3d ) comprises two retaining posts 43 a, 43 b, which are each pivotable about a respective pivot axis A (see also FIG. 2) which runs substantially in a horizontal plane, obliquely relative to the longitudinal direction of the milking station 10. The pivot axes A of the retaining posts 43 a, 43 b are for example arranged at a height of 30 cm. The angle between the pivot axis A of each retaining post 43 a, 43 b and the longitudinal direction of the milking station 10 is around 30° in this exemplary embodiment.

As shown in FIGS. 3a and 3c , in the open state of the neck lock device 18, the retaining posts 43 a, 43 b define a V-shaped opening. A cow 8 walking into the milking station 10 first pushes its head through the central opening 19 between the fence parts 15 a, 15 b, and through the V-shaped opening to reach the drinking trough 17. The V-shaped opening is relatively large so that the cow 8 is encouraged to drink from the drinking trough 17. In the locked state shown in FIGS. 3b, 3d , the retaining posts 43 a, 43 b run substantially vertically. Between them is a retaining opening with a second width w₂ which is smaller than the first width w₁ of the central opening 19 between the fence parts 15 a, 15 b. The width w₂ of the retaining opening is such that a cow 8 which pushes its head through the retaining opening cannot then withdraw it.

The width w₂ of the retaining opening is for example 195 mm. With such a width w₂, a cow 8 locked at the neck cannot withdraw its head fully from the retaining opening, but can still move to some extent in the longitudinal direction of the milking station 10. This freedom of movement is however limited by the fence parts 15 a, 15 b which form a stop for the shoulders of the cow 8. The cow 8 can only move its neck forward through the retaining opening until the shoulders of its front legs come to lie against the fence parts 15 a, 15 b. By restricting the freedom of movement of the cow in the milking station 10, the automatic connection of the milking cups 22 to the teats of the cow 8 becomes easier.

The retaining posts 43 a, 43 b are each connected to one of the fence parts 15 a, 15 b by means of a hinge arm 44 a, 44 b. Each hinge arm 44 a, 44 b consists of two arm parts 45 a, 46 a and 45 b, 46 b respectively, which are mutually pivotably connected by means of a hinge 48. As described above, the neck lock device 18 is actively movable by means of the actuator device 40 between the locked state (see FIGS. 3b and 3d ) and the open state (see FIGS. 3a and 3c ). In this exemplary embodiment, the actuator device 40 of each neck lock device 18 comprises two pneumatic cylinders 42 a, 42 b for moving the respective retaining posts 43 a, 43 b. To control the pneumatic cylinders 42 a, 42 b, these are actively connected to the control system 41.

The pneumatic cylinders 42 a, 42 b engage one of the arm parts 45 a, 45 b of the hinge arms 44 a, 44 b. The other arm parts 46 a, 46 b each comprise a protruding lip 47 which forms a stop for the locked state. When the pneumatic cylinders 42 a, 42 b are extended, the retaining posts 43 a, 43 b move from the open state to the locked state, wherein, because of the obliquely running pivot axes A, the retaining posts 43 a, 43 b at the same time move slightly forward. When the cow 8 is enclosed, the retaining posts 43 a, 43 b approach the neck of the cow 8 not only from the side but also to some extent from the rear, so that the cow 8 does not or scarcely perceives the movement of the retaining posts 43 a, 43 b, even from the corner of its eye. This helps keep the cow 8 quiet during application of the neck lock.

The pneumatic cylinders 42 a, 42 b push the arm parts 45 a, 45 b through a dead point until the lips 47 of the arm parts 46 a, 46 b come to lie against the arm parts 45 a, 45 b. The retaining posts 43 a, 43 b have then reached the locked state. The pneumatic cylinders 42 a, 42 b need not be dimensioned to absorb, in the locked state, forces which the cow 8 may exert to free itself from the neck lock. Such forces are dissipated mechanically via the hinge arms 44 a, 44 b. To open the neck lock 18, the retaining posts 43 a, 43 b are retracted again through the dead point by the pneumatic cylinders 42 a, 42 b.

As described above, the drinking troughs 17 of the drinking system 16 are configured to provide water for the cows 8. In this exemplary embodiment, each drinking trough 17 is provided with a flap or tongue 49, known in itself and operated by the cow, which forms a supply valve. The flap 49 is pretensioned in a closed state. When a cow 8 presses its nose against the flap 49, the flap 49 is moved to an open state and water flows into the drinking trough 17. A sensor 50, for example a flow meter, is provided in the supply line to the drinking trough 17 (see FIGS. 4a-4d ). The sensor 50 is actively connected to the control system 41. On the basis of the sensor 50, it is perceived when the cow 8 presses its nose against the flap 49. The sensor 50 forms a detection means for detecting whether the cow 8 in a milking station 10 has pushed its head into the drinking trough 17 of said milking station 10. The detection means may however also be configured differently, for example with a sensor for detecting whether a light beam is interrupted. It is also possible that the detection means is configured to detect whether the cow in a milking station 10 has brought its head above the drinking trough 17, instead of in the drinking trough 17.

In this exemplary embodiment, the sensor 50 configured as a flow meter measures the quantity of water supplied to each drinking trough 17. On the basis of the quantity of water supplied, the control system 41 can deduce how much water the cows 8 have drunk during a visit to the milking station 10. Therefore the water consumption and drinking behavior of the cows 8 can be monitored individually.

A cow 8 which visits the milking station 10 to drink water from the drinking trough 17 pushes its head through the V-shaped opening between the retaining posts 43 a, 43 b. The transponder 23 in the collar of the cow 8 is read by the readout unit 24 of said milking station 10, so that the cow 8 is identified. Although the readout unit 24 can indeed identify the cow 8 by means of the transponder 23, it cannot be accurately established whether the cow 8 is in the correct position and/or attitude for locking at the neck in the milking station 10. The correct position and/or attitude in the milking station 10 can however be established using the sensor 50. When, after identification by the transponder 23, the cow 8 operates the flap 49 of the drinking trough 17 with its nose, the control system 41 via the sensor 50 establishes that the head of the cow 8 is in the drinking trough 17 and the cow 8 therefore has a position and/or attitude in the milking station 10 which is suitable for locking the cow 8 at the neck by means of the neck lock device 18 of said milking station 10.

When the control system 41 has established that the cow 8 in the milking station 10 has a position and attitude which is suitable for locking said cow 8 at the neck, the control system 41 controls the actuator device 40 of said milking station 10 such that the cow 8 is locked at the neck. The control system 41 for controlling the pneumatic cylinders 42 a, 42 b is configured and programmed such that the retaining posts 43 a, 43 b are only moved from the open state to the locked state if the readout unit 24 has identified the transponder of the cow 8 and established, on the basis of the sensor 50, that the cow 8 is pressing its nose against the flap of the drinking trough 17, i.e. the cow 8 is in the position and attitude in the milking station 10 in which the cow 8 can be reliably enclosed between the retaining posts 43 a, 43 b. In other words, the control system 41 makes use of the combination of the data from the transponder 23/readout unit 24 and the sensor 50 to determine whether the cow 8 in the milking station 10 has the position and attitude suitable for the neck lock.

On readout of the transponder 23 of a cow 8, the control system 41 furthermore determines whether or not the identified cow 8 fulfils the milking criterion, i.e. is/is not ready for milking. According to the invention however, these data are not used to operate the retaining posts 43 a, 43 b from the open state to the locked state. According to the invention, locking the cow 8 at the neck is not dependent on whether the cow 8 fulfils the milking criterion. It is not relevant whether the cow 8 is ready for milking or not: both a cow ready for milking and a cow not ready for milking are locked by the retaining posts 43 a, 43 b of the neck lock device 18. The control system 41 is programmed such that all cows 8 which, on a visit to the milking station 10, assume the position and attitude suitable for the neck lock in the milking station 10, are locked at the neck by means of the neck lock device 18. Each cow 8 which walks into a milking station 10 and then operates the flap 49 of the drinking trough 17 with its nose, is according to the invention then secured at the neck by the retaining posts 43 a, 43 b.

Because the cows 8 are always locked at the neck when, after walking into a milking station 10, the cows 8 begin to drink from the drinking trough 17, the cows 8 rapidly become accustomed to the neck lock 18. Consequently, the cows 8 stand quietly in the milking station 10 when the cows 8 are held at the neck. This is favorable for calmness in the herd, and furthermore has the particularly great advantage that the milking system 20 can easily and quickly automatically connect the milking cups 22 in the case that the cow 8 is ready for milking.

If the cow 8 locked at the neck is not ready for milking, this cow 8 need not be milked. After locking at the neck, the cow 8 may be released again almost immediately. The control system 41 is configured to release every cow 8 not ready for milking after a predefined period, calculated from the time at which the cow 8 is locked at the neck. The predefined period in this exemplary embodiment is around 15 seconds, but may be longer or shorter of course.

If the cow 8 locked at the neck is ready for milking, the control system 41 sends a signal to the milking system 20 to milk said cow 8. The control system 41 is programmed such that the neck lock device 18 remains locked until the milking of the cow 8 is completed. Only when the milking cups have been disconnected is the neck lock device operated by the control system 41 from the locked state to the open state, to release the cow 8. It is preferred that the neck lock device 18 is opened only around 5-30 minutes after disconnection of the milking cups 22. During this period, the teat openings of the milked cow 8 can recover.

As described above, in this exemplary embodiment, the entry openings 11 of the milking stations 10 are permanently accessible for the milking animals 10. The feature of always locking the cows 8 at the neck however may also be used in a system with milking stations which for example comprise an access gate (not shown). In this case, the system according to the invention is preferably configured such that the entry opening 11 of each milking station 10 which is not occupied by milking animal, is left open to allow a cow 8 into the milking station 10, irrespective of whether the cow 8 fulfils the milking criterion. In other words, if the entry openings 11 of the milking stations 10 can be closed by an access gate (not shown), the access gates are operated by the control system 41 so that each access gate of an unoccupied milking station 10 remains open. Every cow 8, irrespective of whether or not the cow complies with the milking criterion, can walk into the free milking station 10.

In the exemplary embodiment shown in FIGS. 1, 2 and 4 a-4 d, the robot device of the automatic milking system 20 is configured as an autonomous self-propelled trolley 21 for connection of the milking cups 22, wherein the trolley 21 is connected to the fixed world by means of a flexible connecting string 5 containing one or more pipes or lines.

The trolley 21 is connected by means of the flexible connecting string 35 to a coupling device 36 which is arranged at a fixed location in the animal-free space 70, for example on a wall of the barn, i.e. the connecting string 35 is connected at one end to the trolley 21 and at the other end to the coupling device 36. The coupling device 36 comprises a first connector device, while the flexible connecting string 35, at the end facing away from the trolley 21, is provided with a second connector device which can be releasably connected to the first connector device. When the first and second connector devices are coupled together, the different pipes or lines of the connecting string 35 are connected. This will be explained in more detail below.

The connecting string 35 is configured such that the trolley 21 can travel over the floor 71 of the animal-free space 70 into each of the milking stations 10, while the trolley 21 remains connected to the coupling device 36 by means of the connecting string 35. For example, the length and stiffness of the connecting string 35 are adapted such that the trolley 21 can travel into each milking station 10, up to below the teats of a cow 8. In this exemplary embodiment, the connecting string 35 is guided in the animal-free space 70 through an eye of a string guide 37 which is movably suspended on a guide rail 38. In this way, the connecting string 35 does not obstruct the trolley 21 in its travel over the floor 71. Such a string guide is however optional.

Although the connecting string 35 in FIGS. 4a-4d is indicated diagrammatically by a single solid line, the connecting string 35 in this exemplary embodiment comprises several pipes or lines, as indicated diagrammatically in FIG. 7. The various pipes or lines of the connecting string 35 are described below.

The connecting string 35 comprises four milk lines 80 a, 80 b, 80 c, 80 d. The four milking cups 22, known in themselves, of the trolley 21 each comprise a teat space and a pulsation space (not shown). In this exemplary embodiment, each milking cup 22 is connected by means of a double-channel hose 66 to a coupling piece 55 which is attached to the trolley 21. Each double-channel hose 66 comprises two channels (not shown). The one channel of the double-channel hose 66 is a milk-carrying channel which discharges a mixture of milk and air from the milking cup 22, while the other channel of the double-channel hose 66 forms a vacuum channel for application of a pulsating vacuum to the teat space of the milking cup 22. The vacuum channel is connected via the coupling piece 55 to a pulsator (not shown), which is attached to the trolley 21.

The four milk lines 80 a, 80 b, 80 c, 80 d of the connecting string 35 are connected at one end via the coupling piece 55 to the respective milk-carrying channels of the double-channel hoses 66. At the other end, the milk lines 80 a, 80 b, 80 c, 80 d are connected to the coupling device 36. The four milk lines 80 a, 80 b, 80 c, 80 d are each connected, via the mutually coupled first and second connector devices of the coupling device 36 and the connecting string 35 respectively, fluid-tightly and/or air-tightly to four milk-carrying lines 57 a, 57 b, 57 c, 57 d which are connected to a milk/air separator 33 for separating milk and air (see FIG. 2). The milk/air separator 33 is formed for example by a milk jar known in itself. The milk/air separator 33 is fixedly arranged in the animal-free space 70.

The milk/air separator 33 is in fluid connection via a milk transport line 34 with a milk storage tank 25 for the cooled storage of milk. The milk storage tank 25 is fixedly placed outside the accommodation space 2, for example in the animal-free space 70 or elsewhere. The milk transport line 34 comprises a milk pump 32 which transports milk from the milk/air separator 33 to the milk storage tank 25. Between the milk pump 32 and the milk storage tank 25, the milk transport line 34 comprises a three-way valve 27 for separating pre-milk and/or milk which is unsuitable for human consumption.

The connecting string 35 furthermore comprises a flexible vacuum line 81 which is in fluid connection with the pulsator attached to the trolley 21. The flexible vacuum line 81 connects the pulsator of the trolley 21 to the coupling device 36. The flexible vacuum line 81 is connected, via the mutually coupled first and second connector devices of the coupling device 36 and the connecting string 35 respectively, air-tightly to a vacuum line 59 which leads to a vacuum source 26. The vacuum source 26 is placed at a fixed location in the animal-free space 70. The vacuum source 26 is for example configured as a vacuum pump, known in itself, with rotation speed control. The vacuum source 26 is furthermore connected by means of a vacuum line 58 to the milk/air separator 33.

In addition, the connecting string 35 comprises a flexible power supply line 85. The power supply line 85 forms part of an electrical connection between the trolley 21 and an electrical power source 31, for example a high-voltage current source. The trolley 21 comprises several electric motors. For example, the trolley 21 in this exemplary embodiment has a drive and steering system for driving and steering the trolley 21. The trolley 21 has two tracks 73, and for each track 73 a respective electric motor is arranged on the trolley 21 (not shown). In addition, the trolley 21 comprises electric motors for moving the milking cups 22 relative to the trolley 21 so that the milking cups 22 can be connected automatically to the teats of a cow 8. For teat detection, the trolley 35 furthermore comprises a camera 74, in particular for producing three-dimensional images. Instead of the camera 74, other teat detection means may also be used. The electric motors and the camera 74 on the trolley 35 are supplied with electrical energy which is supplied via the flexible power supply line 85. At the coupling device 36, the power supply line 85 is connected to a supply cable 64, for example by means of plugs. The trolley 21 in this exemplary embodiment requires no electrical accumulators.

The connecting string 35 furthermore comprises a flexible water line 82, for example a water hose, which is connected at one end to the trolley 21. On the trolley 21, water is used for example to rinse the milking cups 22 after milking. The water line 82 is in fluid connection with the milking cups 22 on the trolley 35 (not shown). At the other end, the water line 82 is connected, via the mutually connected connector devices of the connecting string 35 and the coupling device 36, fluid-tightly to a water supply line 62 which is connected to a water connection 29. The water connection 29 is formed for example by a tap connected to the water mains.

The connecting string 35 is furthermore provided with a flexible compressed air line 83. Compressed air is used for example on the trolley 21 to blow clean a lens of the camera 74 or the milking cups 22 of the trolley 21. The compressed air line 82 is connected at one end to the trolley 21, for example in fluid connection with a nozzle provided on the trolley 21 (not shown). At the other end, the compressed air line 82 is connected, via the mutually connected connector devices of the connecting string 35 and coupling device 36, air-tightly to a compressed air line 61 which is connected to a compressed air source 28.

The connecting string 35 has a flexible data line 86, for example an ethernet cable, which is connected at one end to a control unit arranged on the trolley 21 (not shown). The data line 86 is connected via the control unit of the trolley 21 to the camera 74 of the trolley 35. In this exemplary embodiment, the image signal from the camera 74 is transmitted by the control unit of the trolley 35, via the data line 86, the connected connector devices of the connecting string 35 and of the coupling device 36, and a data cable 65, to the control system 41. On the basis of the image signal of the camera 74, the control system 41 can determine the position of the teats of a cow 8. Via the hard-wired data connection 65, 86, control signals can furthermore be sent by the control system 41 to the control unit on the trolley 21. The drive and steering system of the trolley 21 is controlled depending on the control signals. Data are sent from the trolley 21 to the control system 41 and vice versa via the hard-wired data connection.

In this exemplary embodiment, the connecting string 35 comprises a flexible fluid line 84 for disinfectant fluid, which is in fluid connection with a spray device arranged on the trolley 21 for spraying disinfectant fluid onto the teats of a cow 8. The fluid line 84 for disinfectant fluid is connected in the same manner as described above, via the coupling device 36 and an associated line 63, to a holder 30 for disinfectant. The sprayer device is aimed for example at one or more brushes for pretreatment of the teats of a cow 8 which must be milked. Instead of pretreatment with brushes, the trolley 21 may contain a pretreatment cup for pretreatment of the teats. In this case, the fluid line 84 is connected to the pretreatment cup of the trolley 21.

Also, one or more of the pipes or lines described above of the connecting string 35 may be omitted. For example, the trolley 21 comprises a holder for disinfectant, so that disinfectant need not be supplied to the trolley 21 and the fluid line 84 is not required. In addition to the pipes or lines described above, the connecting string 35 may also comprise other pipes or lines and/or cables.

The milking cups 22 of the trolley 21 are arranged on a robot arm 75 which is movable between a lowered state (see FIGS. 4a-4c ) and a raised state (see FIG. 4d ). In this exemplary embodiment, the robot arm 75 is connected to a chassis of the trolley 21, pivotably between the lowered state and the raised state. The robot arm 75 can be driven by means of an electric drive motor (not shown) which is actively connected with the control system 41. The milking cups 22 of the trolley 35 are tiltable relative to the robot arm 75 between a retracted state (see FIGS. 4 a-c) and an erected state (see FIG. 4d ). In the retracted state, the milking cups 22 lie substantially horizontally, with the openings of the milking cups 22 opposite the direction of travel of the trolley 21, while in the erected state the milking cups 22 are tilted upward, for example extending substantially vertically upward. In this exemplary embodiment, the milking cups 22 are pretensioned in the erected state, for example by means of a spring means, and the trolley 21 comprises a tilt drive for tilting the milking cups 22 from the erected state to the retracted state (not shown). The tilt drive comprises an electric drive motor (not shown). The tilt drive is actively connected to the control system 41.

As shown most clearly in FIGS. 4a-4d , the milking stations 10 each comprise a floor with a first floor part 90 and a second floor part 91 which is raised relative to the first floor part 90. The first floor part 90 is connected below the second floor part 91 to the floor 71 of the animal-free space 70. In this exemplary embodiment, the floor 71 of the animal-free space 70 and the first floor part 90 form a cohesive floor. The trolley 21 can travel over the flat floor 71 of the animal-free space 70, under the second floor part 91, onto the first floor part 90 of each milking station 10.

The raised second floor part 91 is arranged for example 20 cm higher than the first floor part 90. Such a raised position corresponds in principle to the normal height difference between a lying stall and the floor in a barn. The length of the second floor part 91, viewed in the longitudinal direction of each milking station 10, is such that when a cow 8 stands in the milking station 10 with its front legs on the second floor part 91, the rear legs of said cow 8 stand on the first floor part 90. The length of the second floor part in this exemplary embodiment is 50 cm. A cow 8 in a milking station 10 can only drink from the drinking trough 17 of said milking station if the cow 8 stands with its front legs on the second floor part 91. When the cow 8 stands with its front legs on the second floor part 91, the cow 8 has a position and/or attitude which is suitable for connecting the milking cups 22 of the trolley 21 to the teats of said cow 8.

When a cow 8 visits one of the milking stations 10 to drink from the drinking trough 17 and said cow 8 is ready for milking, the control system 41 controls the trolley 21 so that the trolley 21 travels automatically over the floor 71 of the animal-free space 70, onto the first floor part 90 of said milk station 10, to under the teats of said cow 8. Since only a restricted height is available under the second floor part 91, the trolley 35 with erected milking cups 22 is unable to travel below the second floor part 91, even if the robot arm 75 is lowered.

To enable the trolley 21 to travel from the floor 71 of the animal-free space 70, under the fence 14 and the second floor part 91, the milking cups 22 of the trolley 21, with the robot arm 75 in the lowered state, are tilted down into the retracted state. The trolley 21 then fits under the second floor part 91 (see FIG. 4c ). After the trolley 21 has passed under the second floor part 91, the control system 41 controls the electric drive motor of the robot arm 75 to bring this into the raised state, and the tilt drive to move the milking cups 22 to the erected state. Then the milking cups 22 are connected automatically to the teats of the cow 8 on the basis of control signals from the control system 41. The trolley 21 can be moved inside the milking station 10 and/or the robot arm 75 can be controlled relative to the trolley 21 to connect the milking cups 22 automatically to the teats of a cow 8 in the milking station 10.

During travel over the floor 71 of the animal-free space 70, and up to the first floor part 90 of the milking station 10, the trolley 21 remains connected to the coupling device 36 by means of the flexible connecting string 35. Since the pipes or lines of the connecting string 35 are used to discharge the milk, to supply a vacuum, water, compressed air and disinfectant, and to exchange data, the trolley 21 can be configured particularly light and compact.

Also, in an embodiment not shown, according to the invention it is possible that milk and air discharged from the milking cups 22 are separated from each other on the trolley 21. For example, the milking cups 22 are each connected to a milk/air separator which is arranged on the trolley 21. The milk/air separator of the trolley 21 has a milk discharge opening which is in fluid connection with a milk pump arranged on the trolley 21. The milk pump is connected to a single flexible milk line which extends through the connecting string 35 to the coupling device 36. Only milk flows through the flexible milk line of the connecting string 35. Only one milk line is required for transporting the milk. The milk is discharged from the coupling device 36 to the milk storage tank 25 as described above. Since the milk pump in this case is arranged on the trolley 21, the milk can be transported from the trolley 21 to the milk storage tank 25 particularly efficiently.

In a further embodiment (not shown), according to the invention, the system comprises two or more autonomous self-propelled trolleys. For example, a second trolley contains a device for pretreatment and/or post-treatment of the teats of a cow 8 in a milking station 10. The second trolley can pretreat, for example clean, disinfect and/or stimulate, the teats of the cow 8 in a milking station 10, before the first trolley 21 automatically connects the milking cups 22 to the teats. In addition or alternatively, the second trolley may be configured to post-treat the teats of the milk cow 8, i.e. after the first trolley 21 has milked the cow 8 and travelled away, the second trolley travels under the milk cow 8 for post-treatment. Therefore firstly the pretreatment and/or post-treatment, and secondly the milking, are carried out by different trolleys. Also, a second trolley may be configured in the same way as the first trolley.

An alternative embodiment of the system is shown in FIGS. 5, 6 a-6 c. The same or similar components carry the same reference numerals. In this case, the system comprises a telescopic robot arm 100. The telescopic robot arm 100 comprises several arm parts 101 a, 101 b, 101 c, 101 d which are telescopically connected to each other. By extending and retracting the arm parts 101 a, 101 b, 101 c, 101 d, the robot arm 100 can be moved in the longitudinal direction of the milking station 10. The first arm part 101 a of the robot arm 100 is fixed to an arm guide 105 which is connected to a fixed supporting structure. In this exemplary embodiment, the supporting structure comprises a guide rail 106 connected to the floor 71 of the animal-free space 70. The arm guide 105 with the robot arm 100 attached thereto is guided movably over the guide rail 106 by means of rollers, in the transverse direction of the milking stations 10. The function of the robot arm 100 is furthermore substantially the same as that of the trolley 21 described above, and will not therefore be explained further. It is also possible that the flexible connecting string 35 on the robot arm 100 is configured differently, for example is replaced by pipes, lines and/or cables which are arranged on the robot arm 100.

Although the guide rail 106 in this exemplary embodiment is attached to the floor 71 of the animal-free space 70, the guide rail 106 for the arm guide 105 may also be suspended. The robot arm 100 may furthermore, instead of a telescopic arm, also be configured as a robot arm with several arm parts connected pivotably relative to each other (not shown). Instead of a robot arm 100 which can perform a rectilinear movement transversely relative to the milking stations 10, according to the invention it is also possible that the robot arm is connected to a fixed supporting structure about a substantially vertical pivot axis, for example by means of a ball joint. In this case, the milking stations may be placed around the pivot axis, i.e. the milking stations then lie laterally next to each other in an arc, such that the milking stations are oriented with their head sides substantially towards the pivot axis. By pivoting the robot arm, the robot arm can be aligned with each of the milking stations so that the robot arm can connect milking cups in each milking station. Such robot arms for connection of milking cups 22 may be designed and produced using techniques known in themselves in practice.

The robot arm 100 shown in FIGS. 5, 6 a-6 c is provided with milking cups 22. The milking cups 22 are arranged on the robot arm 100. During operation, the robot arm 100 connects the milking cups 22 one by one to the teats of a cow 8. It is however also possible that the milking system 20 is provided with a milking cup holder (not shown), configured for holding the milking cups 22 which are not being used. The robot arm 100 in this case comprises a gripper member (not shown), which is configured to take at least one milking cup 22 from the milking cup holder and connect this to a teat of a cow 8. During operation, the robot arm 100 takes a first milking cup 22 from the milking cup holder and connects said milking cup to a teat, then the robot arm 100 takes a second milking cup 22 from the milking cup holder, and so on. Also, such a robot arm can be produced using techniques known in themselves in practice. The milking cup holder with a set of milking cups 22 may be arranged in the animal-free space 70, or such a milking cup holder with a set of milking cups 22 may be arranged in each milking station 10. With such a robot arm 100, each milking station 10 may comprise a set of milking cups 22. The milking cups 22 are for example arranged in sets in the animal-free space 70 in front of each milking station 10 or in each milking station 10, for example close to the teats of a cow 8. It is also possible that a common set of milking cups 22 is shared by several milking stations 10. The milking cups 22 are then used successively in several milking stations 10.

After a cow 8 has been milked, in the exemplary embodiments described above, said cow 8 may remain in the milking station until the cow 8 voluntarily leaves the milking station, unless the cow 8 complies with a predefined expulsion criterion and all milking stations 10 are occupied by other cows. As indicated diagrammatically in the figures, each milking station 10 comprises an expulsion means 110 for driving a cow 8 out of the milking station 10. The expulsion means 110 may be activated, in each of the milking stations 10, to give an expulsion stimulus to a milking animal present in the milking station 10, to encourage it to leave the milking station 10. The expulsion means 110 may be configured in various ways, for example for administering an electric shock to a cow 8 in the milking station 10. Alternatively or additionally, the expulsion means 110 may be configured to give a cow 8 an expulsion stimulus in the form for example of a light signal, an audible signal or a contact signal, such as by means of a water-jet, an air pulse, or a mechanical push or contact element. Also, according to the invention it is possible that the expulsion means are movable relative to the milking stations 10, such that an expulsion stimulus can be given in each milking station 10 to a cow 8 present in said milking station 10 (not shown). Furthermore, according to the invention it is possible that the system 1, instead of or in addition to the expulsion means 110, has an attraction means and/or other motivation means for giving a stimulus in order to entice the cows 8 to leave the milking stations, for example by means of feed concentrate.

To be able to activate the expulsion means, the expulsion means 110 are each actively connected to the control system 41. The control system 41 controls the expulsion means 110 such that the expulsion means 110 are only activated if two conditions are fulfilled: (i) a cow 8 in one of the milking stations 10 fulfils the predefined expulsion criterion, and (ii) all milking stations 10 are occupied. The expulsion criterion may comprise different parameters. For example, the expulsion criterion is dependent on the milking criterion, such as whether the cow 8 fulfils the milking criterion or fulfils the milking criterion within a predefined period, and/or the visit behavior of the cow 8, such as the expected time between two successive visits of the cow 8 to the milking stations, and/or the drinking behavior of the cow 8, such as the water intake, i.e. how much the cow 8 drinks from the drinking trough, and/or other parameters. The expulsion criterion may furthermore be determined individually for each individual cow 8 in the accommodation space 2. Also with a cow-dependent milking criterion however, an expulsion criterion may be used which is the same for all cows 8 in the accommodation space 2.

As described above, the number of milking stations 10 according to the invention is selected such that it does not occur or rarely occurs that all milking stations 10 are occupied simultaneously, i.e. during operation, almost always one or more milking stations 10 are free. Since a cow 8 is only expelled from the milking station if condition (ii) is fulfilled, i.e. all the milking stations are occupied, a cow 8 is driven out only in very exceptional cases. This has a positive effect on the extent to which the cows 8 voluntarily visit the milking stations 10. The system according to the invention is configured to allow every cow 8 visiting a milking station 10 to remain there in principle until said cow 8 voluntarily leaves the milking station. The milking animals are only subjected to expulsion stimuli, which are perceived by the cows 8 as uncomfortable, in the exceptional circumstance that all milking stations 10 are occupied. In addition, the control system 41 also determines whether the cow 8 to be driven out complies with the predefined expulsion criterion.

Instead of driving out cows by means of the expulsion means 110 only in very exceptional circumstances, according to the invention it is also possible to allow the cows always to remain in the milking stations until the cows voluntarily leave the milking stations. In this case, no expulsion means 110 are required, i.e. the expulsion means 110 are omitted in this embodiment (not shown). None of the milking stations 10 comprises expulsion means. Also, the system does not comprise any attraction means or other motivation means for encouraging the cows 8 to leave the milking stations. The cows 8 may remain in the milking stations 10 until the cows 8 voluntarily leave the milking stations 10. As described above, the cows 8 have access to the milking stations 10 irrespective of whether or not the cows 8 fulfil the milking criterion, i.e. irrespective of whether the cows 8 must be milked. Both cows 8 which have been milked, and cows 8 which visit the milking stations 10 to drink without needing to be milked, may remain in the milking stations 10. In this case, it cannot be completely excluded that all milking stations 10 are occupied at some time by the cows 8. If all milking stations 10 are occupied, a cow 8 from the accommodation space 2 which wishes to drink, must wait until one of the cows 8 voluntarily leaves the milking station 10. As explained above, the number of milking stations 10 is however sufficiently great, relative to the number of cows 8 contained in the accommodation space 2, that the risk is minimal that all milking stations 10 will remain occupied simultaneously for an unacceptable period.

An alternative embodiment of the system shown in FIG. 8. The same or similar components carry the same reference numerals. In the embodiment shown in side view of FIG. 8, the animal-free space also comprises a lowered floor 200 which extends below the level of the connection through which the trolley 21 can travel, whereby the animal-free space is lowered relative to the milking stations 10. Thus the system still comprises the animal-free space 70 which is closed for the milking animals 8 and extends adjacent to the milking stations 10, and wherein the floor 90 of the milking station 10 is connected to the floor 71 such that the trolley can travel from the animal-free space 70 via floor 71 to the floor part 90 of the milking station. However, the animal-free space in addition has the lowered floor 200 which lies below the level of the floor 71 and the floor part 90 over which the trolley can travel. The lowered floor extends under both the floor 71 over which the trolley can travel and partly also below the floor part 90 of the milking station. In practical terms, the animal-free space is thus lowered below the level of the milking stations, which makes this particularly suitable for use in existing milking carousels or milking pits, with few conversion measures. A milking carousel or milking pit already has an animal-free space with a floor which is lower than the floor of the milking stations. Maintenance of the trolley 21 is now easy to implement because personnel standing on the lowered floor 200 of the animal-free space can easily reach the level of the floor 71 with the trolley 21. The floor over which the milking animals can walk is indicated with the dotted line 291, and connects the milking station 10 to another part of the accommodation space 2. This walkable floor 291 lies above the floor 71 on which the milking trolley can travel, and extends further above the animal-free space. The animal-free space can thus be configured as a cellar; in FIG. 8 the walls of such a cellar are not shown. The roof of the cellar is, at least partly, formed by this floor 291. The roof 291 connects to the accommodation space, whereby the animals can walk from the milking station via the cellar roof to the accommodation space. In FIG. 8, the milking animal can walk from the milking station 10 straight over the raised floor part 91 and via a closable passage (not shown) at the end of the milking station, over the walkable floor 291, to another part of the accommodation space 2, or to a further accommodation space, such as a separation space or a grazing space (not shown).

The invention is not restricted to the exemplary embodiments shown in the drawing. The person skilled in the art may make various adaptations which lie within the scope of the invention. The features described above may be used both separately and in any arbitrary combination, and/or be combined with one or more features according to one or more of the claims which follow. In particular, according to the invention, the drinking system with drinking troughs 17 may be replaced by a feed and/or drinking system for providing feed and/or water for the milking animals. The feed and/or drinking system comprises for example a feed and/or drinking trough for each milking station. The milking animals then visit the milking stations to eat and/or drink. Furthermore, according to the invention, it is possible that the system, instead of the neck lock device described in the description and claims, comprises another holding device for securing and/or holding a milking animal in a milking station. For example, each milking station has a holding device which can be operated by means of an actuator device between a holding state, in which a milking animal present in said milking station is held by the holding device, and a free state, in which a milking animal present in said milking station is free to leave said milking station. Such a holding device for example comprises a door or gate to enclose a milking animal in a milking station, such as in a generally known milking stall. 

1. A system for milking a group of milking animals wherein the system comprises: an accommodation space for the milking animals, a milk storage tank, an automatic milking system for automatic milking of milking animals, wherein the milking system comprises at least one autonomous, self-propelled trolley with milking cups, and wherein the milking system is configured for the automatic connection of the milking cups of the trolley to the teats of a milking animal, and wherein the milking cups of the trolley are connected to the milk storage tank by means of a milk discharge system, which comprises a flexible milk line connected to the trolley, the system further comprises: a plurality of milking stations each arranged at a fixed position and next to each other, wherein the milking stations each comprise an entry opening for entry of a milking animal from the accommodation space to said milking station, an animal-free space which is closed for the milking animals in the accommodation space and extends adjacent to the milking stations, wherein the animal-free space is connected to each milking station by means of a connection through which the trolley can travel, and wherein the milk storage tank is placed at a fixed position outside the accommodation space, and the flexible milk line is configured such that the trolley can travel from the animal-free space into each of the milking stations while the milk line remains connected to the trolley.
 2. The system as claimed in claim 1, wherein the milk discharge system is provided with a plurality of flexible milk lines, which are each connected at one end to the trolley and are each in fluid connection with one of the milking cups, and a milk/air separator which is arranged in the animal-free space, and wherein each milking cup of the trolley is connected respectively via one of the flexible milk lines to the milk/air separator, and wherein the flexible milk lines are each configured such that the trolley can travel from the animal-free space into each of the milking stations while the milk lines each remain connected to the trolley.
 3. The system as claimed in claim 1, wherein the milk discharge system comprises a milk/air separator which is arranged on the trolley, and wherein the milking cups are each connected to the milk/air separator, and wherein the milk/air separator comprises a milk discharge opening which is in fluid connection with the end of the flexible milk line connected to the trolley, and wherein the trolley is provided with a milk pump for pumping milk via the flexible milk line to the milk storage tank.
 4. The system as claimed in claim 1, wherein the milking system comprises a vacuum source which is arranged in the animal-free space, wherein the vacuum source is connected via a vacuum system to the milking cups for applying a vacuum to the milking cups, and wherein the vacuum system comprises a flexible vacuum line which is connected to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the vacuum line remains connected to the trolley.
 5. The system as claimed in claim 1, wherein the milking system comprises an electric power supply source which is arranged in the animal-free space, and wherein the trolley is connected to the power supply source by means of an electrical connection, wherein the electrical connection comprises a power supply line which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the power supply line remains connected to the trolley.
 6. The system as claimed in claim 1, wherein the milking system comprises a water connection which is arranged in the animal-free space, and wherein the trolley is connected to the water connection by means of a water supply system comprising a flexible water line, which is connected at one end to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the water line remains connected to the trolley.
 7. The system as claimed in claim 1, wherein the milking system comprises a compressed air source which is arranged in the animal-free space, and wherein the trolley is connected to the compressed air source by means of a compressed air system comprising a flexible compressed air line, which is connected to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the compressed air line remains connected to the trolley.
 8. The system as claimed in claim 1, wherein the milking system comprises a control system, and wherein the trolley is connected to the control system by means of a hard-wired data connection comprising a flexible data line, which is connected to the trolley and is configured such that the trolley can travel from the animal-free space into each of the milking stations while the data line remains connected to the trolley.
 9. The system as claimed in claim 1, wherein the milking system is provided with a coupling device which is arranged at a fixed position in the animal-free space, and wherein the trolley is connected to the coupling device by means of a flexible connecting string which is configured such that the trolley can travel from the animal-free space into each of the milking stations while the connecting string remains connected to the trolley, and wherein the connecting string comprises the milk line and/or a vacuum line and/or a power supply line and/or a water line and/or a compressed air line and/or a data line.
 10. The system as claimed in claim 9, wherein the coupling device comprises a first connector device, and wherein the flexible connecting string, at an end remote from the trolley, is provided with a second connector device, which can be releasably coupled to the first connector device for connecting the milk line and/or the vacuum line and/or the power supply line and/or the water line and/or the compressed air line and/or the data line.
 11. The system as claimed in claim 1, wherein the animal-free space also comprises a lowered floor which extends below the level of the connection through which the trolley can travel, whereby the animal-free space is lowered relative to the milking stations.
 12. The system as claimed in claim 1, wherein the animal-free space comprises a floor, and wherein each milking station comprises a floor provided with a first floor part which is connected, via a connection through which the trolley can travel, to the floor of the animal-free space, and a second floor part which is raised relative to the first floor part, and wherein the trolley is configured to travel from the floor of the animal-free space at each milking station, under the second floor part, to the first floor part of said milking station and back.
 13. The system as claimed in claim 12, wherein the milking cups of the trolley can be tilted between a retracted state in which the trolley with the milking cups can travel under the second floor part, and an erected state in which the milking cups are tilted up relative to the retracted state.
 14. The system as claimed in claim 12, wherein the milking stations comprise at least one feed and/or drinking trough which is arranged at the head ends of the milking stations opposite the entry openings, such that the milking animal present in one of the milking stations must stand with its front legs on the second floor part of said milking station in order to eat and/or drink from the feed and/or the drinking trough.
 15. The system as claimed in claim 1, wherein the system is provided with a second autonomous, self-propelled trolley which is provided with a device for pretreatment and/or post-treatment of the teats of a milking animal present in a milking station.
 16. The system as claimed in claim 1, wherein the accommodation space is configured to keep a predefined number of milking animals, and wherein the number of milking stations is adapted to the predefined number of milking animals such that the system comprises at least one milking station for every 20 milking animals, preferably at least one milking station for every 15 milking animals, even more preferably at least one milking station for every 10 milking animals.
 17. A method for milking a group of milking animals in a system as claimed in claim 1, and wherein the method comprises: identification of a milking animal in one of the milking stations, determining whether said milking animal complies with a predefined milking criterion, when said milking animal complies with the predefined milking criterion: travel of the trolley from the animal-free space to said milking station, automatic connection of the milking cups of the trolley to the teats of said milking animal, milking of said milking animal by means of the milking system in said milking station, disconnection of the milking cups from the teats of said milking animal, return of the trolley from the milking station to the animal-free space.
 18. The method as claimed in claim 17, wherein a coupling between a first connector device of a coupling device and a second connector device of a connecting string is released, and the trolley with the connecting string is then replaced by a second trolley with a second connecting string which corresponds to a connecting string of the replaced trolley, wherein the second connector device of the second connecting string of the second trolley is releasably coupled to the first connector device of the coupling device. 